I know what you're talking about, when I was in like grade 1 the school computers all had the turbo buttons, however I don't even know if they worked or what they did since I don't recall any difference in performance when they were pushed, but this was like 10 years ago so I have no idea.
Ironically my engineering course I took a while ago salvaged computers that were going in the trash, and they were the same retro pentiums with the turbo buttons. We got to take them apart and rebuilt them (we finally got a budget passed and we get good AMD64s next year
) since that was all the school had that they wanted taken apart since they were basically trash. I had no idea which pins on the board to connect the turbo button too so the mystery remains unsolved.
Google, however, uncovers the mystery.